Method of producing antiseptic articles



United States Patent METHOD OF PRODUCBWG ANTISEPTIC ARTICLES Sylvan I.Cohen, Flushing, and Martin S. Frant, Ossining, N.Y., and Frank J. Sowa,Cranford, N.J.; said Cohen and said Frant assignors to GaliowhurChemical Corporation, New Yorlr, N.Y., a corporation of New York NoDrawing. Fiied July 19, 1954, Ser. No. 444,361

4 Ciaims. (Cl. 117-1385) The present invention relates to antisepticarticles such as nylon, nylon filaments and brushes, particularlytoothbrushes having synthetic plastic heads and handles with nylonbristles, and to the production of such antiseptic articles by treatingthem with solutions of phenyl mercury compounds to provide them with adurable, chemically adherent deposit having excellent germistatic andgermicidal properties, together with great stability and high resistanceto leaching.

In our application Ser. No. 443,423, filed July 14, 1954, now abandoned,we have described and claimed certain solutions of phenyl mercurycompounds, the production of such solutions and the results which can beachieved therewith. These solutions are especially suited or adapted forapplication to various articles, particularly those composed of nylon orhaving a nylon component such as nylon bristles, and the presentinvention is directed to the method of treatment of such articles withsuch solutions and to the antiseptic articles thereby produced.

In accordance with the invention and as a specific example thereof,nylon in filamentary form suitable for the fabrication of toothbrush andother bristles is passed through a bath of phenyl mercury lactate inlactic and formic acids in a continuous manner at such a rate that everyportion of the nylon is wetted with the solution for approximately oneminute. It is to be understood, however, that alternatively, the nylonor other article may be subjected to the solution of the phenyl mercurycompound in other ways, as by immersion or spraying. The processing iscarried out at room temperature and after the nylon has had theindicated length of contact with the solution it is then dried undergentle drying conditions as by means of Warm air currents or lowtemperature drying ovens, except that where time permits the treatedarticle may be allowed to dry in the air under ambient temperatureconditions. It has been found best, and is therefore preferred, tosubject the nylon or other article to the action of the solution for aperiod of about one minute as above indicated, but the precise timefactor in any given instance depends somewhat upon the nature of thearticle and its physical configurations and size and, in general, wehave found that treatment with the solution from about ten to sixtyseconds is adequate, but that treatments up to one hour or more arepermissible without adversely affecting the results, although such isunnecessary.

The bath or solution through which the nylon or other article is passedor in which it is immersed is essentially composed of phenyl mercurylactate in lactic and formic acids, the amount of formic acid beingsufiicient to provide free formic acid in the final solution and toreduce the content of equivalent mercury of the solution toapproximately l%. The equivalent of mercury may, however, range fromapproximately 0.25 to 5% but for best and most economical resultsapproximately 1% of mercury is preferable. Instead of employing phenylmercury lactate, we may utilize any phenyl mercury compound which, withlactic acid, forms phenyl mercury lactate. Examples of such phenylmercury compounds are phenyl mercury acetate and phenyl mercuryhydroxide.

In processing nylon and other articles with the aforementionedsolutions, it is important to avoid any drastic treatments or conditionswhich would cause adverse alteration or change in the nature of thesolutions or the articles themselves, particularly in view of the factthat solutions containing phenyl mercury lactate and lactic and formicacids are rendered unstable at temperatures approximating the boilingpoint of Water. For instance, when such a solution is subjected toboiling for purposes of concentrating it, as has been heretoforeproposed, a reducing action occurs resulting in the formation ofmetallic mercury as a precipitate and a reduction in the equivalentmercury content of the supernatant liquid. Such boiled solutionstherefore lack stability and are not suitable for shipment and treatmentof articles at considerable distances from the point of production ofthe solutions. We, therefore, carry out treatment of the articles withthese solutions at or about room temperature and in any event avoiding atemperature which would adversely aifect the solutions. Since entirelysatisfactory results are obtainable at room temperatures, it is neithernecessary nor desirable to raise the temperature of the treatingsolution although there is no objection to warming the solution or usingit in localities or at times when the ambient atmospheric temperature ishigh.

The nylon or other article or material may be processed in accordancewith the invention at any convenient stage in the manufacture orfabrication of such article or material. Thus, nylon in sheet,filamentary or other physical form or shape may be treated and theantiseptic nylon thus produced may be subsequently finished andincorporated into the final articles, such as brushes. The invention isparticularly adapted for the treatment of toothbrushes having syntheticplastic heads and handles with nylon bristles, although other materialsmay be satisfactorily rendered antiseptic, such as Siberian pig bristlesand those plastices and materials which are commonly employed in themanufacture of brushes and other articles.

Articles treated with the solutions above referred to and then driedunder mild drying conditions are found to be provided with a chemicallyadherent, integrated deposit of a phenyl mercury compound. Thischemically adherent deposit'is characterized not only by excellentgermistatic and germicidal activity but by resistance to leaching bywater and by dentifrices or detergents. The chemical adherence is sostrong and tenacious that it persists for the useful life of the articleitself. In the case of nylon bristles of toothbrushes, tests have shownthat, after treatment, such bristles contain the equivalent ofapproximately (MS-0.030% mercury, which, even under accelerated leachingtest conditions, is reduced by only about 0.001% per day, so that, underthe normal or usual conditions of use, the chemically adherent depositlasts throughout the useful life of the article.

Formic acid appears to play a vital role in the effective treatment ofnylon articles, toothbrushes and other brushes and articles with the newsolutions. In the absence of the formic acid, the results of theinvention cannot be obtained. The formic acid appears to contributedurability and resistance to leaching and, when formic acid isincorporated, tests showed practically no loss of initial activity afterminutes of brushing, whereas, when formic acid was omitted, comparativetests showed practically no activity after only 45 minutes of brushing.

For eifective results, a phenyl mercury compound must r and articles.

be used which is of a selective character in that all phenyl mercurycompounds do not produce useful results. This was found to be true, forexample, with phenyl mercury linoleate. Therefore, in accordance withthe present invention, the solution must contain phenyl mercury lactateor a phenyl mercury compound such as the acetate or hydroxide which,with lactic acid, forms phenyl mercury lactate and lactic acid and, inaddition, formic acid must be present in an amount sufiicient to providesome free formic acid in the solution and also to bring the equivalentof mercury to the desired value in the range of 0.25 to 5%, a 1%equilavent of mercury having been found to be best.

Antiseptic articles produced in accordance with the invention areantiseptic or bacteriostatic by the standards of the Food and DrugAdministration circular 198 method for bristles measuring 0.5 mm. inthickness and 8.0 mms. in length. The inhibitory zone must be at least6.5 x 8.0 mms. if the bristles are severed to the above length fortesting after treatment. Nylon bristles rendered anti-, septic inaccordance with the invention meet this requirement and furthermoreexhibited suflicient bacteriostasis and resistance to further loss ofactivity even after brushing tests of 300-390 minutes.

The term ,nylon is used herein in the same sense as in our aforesaidapplication. The invention is applicable, however, to other syntheticplastics and materials, such as'butyrate resin and the plastics commonlyemployed for toothbrush heads and handles and for other brushesTreatment of such articles in accordance with this invention does notdissolve, alter or otherwise undesirably attack such materials and doesnot reduce their useful life. It is to be further noted that the treatedbristles or other articles show bactericidal killing action and,consequently, the invention. produces results beyond bacteriostasis. Thetests for bactericidal activity were made in accordance with those setforth in our aforesaid application which show that, where contactoccurred from 1-7 hours, most of the subcultures (in the proporcoccuspyogenes var. aureus) had been killed and that where contact occurredfor about 24 or more hours during the tests all subcultures failed togrow.

We claim:

a 1. A method of producing antiseptic nylon and plastic articles whichcomprises subjecting such articles to treatment with a solution ofphenyl mercury lactate in lactic acid and suificient formic acid toreduce the equivalent mercury content to about 0.25-5% and drying thearticles, thereby producing a chemically adherent deposit of phenylmercury formate in and on said articles to render the articles durablygermistatic and germicidal through out their'useful life.

2. The method of claim 1, in which the articles are nylon in filamentaryform and are continuously passed through a bath of the said, solution ata rate such that every portion thereof is immersed in the solution atroom temperature for at least about 10-60 seconds.

3. The method. of claim 1, in which the articles are plastic brusheswith nylon bristles. I

4. The method of claim 1, in which the equivalent mercury content isapproximately 1%.

References Cited in the file of this patent UNITED STATES PATENTS2,099,888 Hill Nov. 23, 1937 2,411,815 Sowa Nov. 26, 1946 2,423,261 SowaJuly 1, 1947 2,423,262 Sowa July 1, 1947 2,479,275 Sowa Aug. 16, 19492,507,299 DAlelio May 9, 1950 2,637,677 Diner stein 'May, 5, 1953FOREIGN PATENTS 543,291 Great Britain Feb. 18, 1942 OTHER REFERENCESRayon and Synthetic Textiles (May 1950), vol. 31, No. 5.

Textile Colorist (February 1940), page 92.

